Free Essay On The Four Forces Of Evolution

Evolution is the changes in gene frequency in a population from one generation to another. A species is a group of organisms having many characteristics and qualities in common. Organisms that belong to the same species can reproduce and sexually interbreed to produce fertile offspring. One species, however, cannot interbreed with members of another species. All organisms that belong to the same group or species make up a population. A population can be defined as a group of organisms that belong to the same species who inhabit the same geographical area and who are capable of interbreeding. Example of a population is humans. Variation or genetic variation defines the genetic differences and characteristics among individuals of the same species. Variation is brought about by environmental effects or genetic differences. Variation can be observed in a species through physical appearance and behavior or traits. The characteristics in a group of organisms can be observed or identified in different levels.
The four forces of evolution include gene flow, genetic drift, selection and mutation. Gene flow refers to the process by which genes are carried down from one population to another. Gene flow can also be termed as migration; it involves the movement of genes from one population where they exist to where they dint exist before hence carrying new genetic material to that population. Genetic drift is a process in which a change in the gene pool or gene variants (alleles) survives strictly by chance over time. The survival of any particular genes is primarily based on chance. It normally occurs in small populations.
Selection is a process in which the best-adapted organisms to a particular environment stand a higher chance of surviving. Selection causes the organisms that are well adapted to a particular environment produce or give rise to more offspring that makes them have a survival advantage over other organisms. Selection can be either natural or artificial. In natural selection, the environment is the agent of selection whereby in artificial selection is done by humans who decide on the members that are to breed. The last force of evolution is mutation. Mutation is a change of the DNA of an organism that in turn leads to changing many aspects of its life. Changes that can occur include physical or behavioral changes. Mutation may occur due to damage to the DNA or problems in the replication process.
Speciation is defined as the process by which new definite biological species are formed from one parent species in the process of evolution usually as a result of genetic isolation from the main population. Speciation also may occur artificially due to agriculture or laboratory experiments that bring about new species. The process by which some properties or traits prevent species from interbreeding or fusing is known as isolation mechanism. Due to genetic isolation, the difference between gene pools in a species become so massive leading to them not being able to interbreed. As a result, a new species are formed with a gene that is genetically distinct or definite from the parent or primary population. The properties that prevent species from interbreeding include geographic, ecological or physiological properties. These features maintain the integrity of a particular species over a period of time by reducing impending gene flow between individuals of different species which in turn maintains or conserves the distinct characteristics and qualities of a species (Daniel & Stewart 1998).
All the forces of evolution affect or have significant impacts on the development of different species as discussed above. The continuity or survival of species is dependent on many properties and aspects that ensure that the best adaptive species inhabit a certain area at a given time which in turn forms a population. The forces of evolution affect and have a significant impact on the evolution process. The continuity and survival of species to newer generations is dependent on these forces. The environment has a way of eliminating or doing away with organisms that are not best suited or adapted to a particular ecological environment that in turn provides a balance in population.

Works Cited

Daniel, Howard &Stewart, Berlocher. Endless Forms: Species and Speciation. New York: Oxford University Press, 1998. Print.